Learn about new insights into the Chesapeake Bay impact crater, which was created by America’s largest asteroid impact; why birds sing; and why your bruises change colors while they heal. In this podcast, Cody Gough and Ashley Hamer discuss the following stories from Curiosity.com to help you get smarter and learn something new in just a few minutes: You Can Still See the Destruction from America's Largest Asteroid Impact — https://curiosity.im/2KKF1ji Why Do Birds Sing? — https://curiosity.im/31WBWlQ Why Do Bruises Change Color? — https://curiosity.im/2ZuFgDn Download the FREE 5-star Curiosity app for Android and iOS at https://curiosity.im/podcast-app. And Amazon smart speaker users: you can listen to our podcast as part of your Amazon Alexa Flash Briefing — just click “enable” here: https://curiosity.im/podcast-flash-briefing.
Learn about new insights into the Chesapeake Bay impact crater, which was created by America’s largest asteroid impact; why birds sing; and why your bruises change colors while they heal.
In this podcast, Cody Gough and Ashley Hamer discuss the following stories from Curiosity.com to help you get smarter and learn something new in just a few minutes:
Download the FREE 5-star Curiosity app for Android and iOS at https://curiosity.im/podcast-app. And Amazon smart speaker users: you can listen to our podcast as part of your Amazon Alexa Flash Briefing — just click “enable” here: https://curiosity.im/podcast-flash-briefing.
Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/why-birds-sing-why-bruises-change-color-and-americas-largest-asteroid-impact
CODY: Hi! We’re here from curiosity-dot-com to help you get smarter in just a few minutes. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about new insights into America’s largest asteroid impact; why birds sing; and why your bruises change color while they heal.
CODY: Let’s satisfy some curiosity.
You Can Still See the Destruction from America's Largest Asteroid Impact — https://curiosity.im/2KKF1ji (Ashley)
A giant asteroid devastated the East Coast of the United States 35 million years ago. And a recent study used fresh dating techniques on the region to show just how devastating it was. The study was published in June 2019 in the journal Meteoritics & Planetary Science, and it focused on a crater we only discovered in the 1990s thanks to a drilling project.
I’m talking about the Chesapeake Bay impact crater, which is a huge divot in the Earth, about 25 miles across. It's the largest crater in the U.S. and the fifteenth largest in the world.
While the crater remains hidden, its evidence is far-reaching. After the asteroid hit, it threw off a huge layer of material that covers a zone about 10 times the size of Texas. This includes tekties — natural glass that forms after space rocks hit the Earth — and shocked zircon crystals. A science team looked at drilling samples from the crater and dated them with a new technique for the first time, which helps narrow down exactly when the impact happened.
You might think zircon is just a pretty gemstone, but there's more to this mineral than meets the eye. Preserved in the zirconium silicate crystals generated by this impact is an echo of the shock pressures and high temperatures that the asteroid generated when it crashed into Earth. These crystals are also small and hard to study since they’re only about as thick as a human hair.
Scientists examined crystals found about 250 miles northeast of the impact site using a technique called uranium-thorium-helium dating. Radioactive elements like uranium and thorium naturally decay into more stable elements over time — in this case, helium. Since the decay takes place at a predictable rate, scientists can precisely date samples by looking at ratios of the different elements contained within these samples.
The team studied a variety of crystals and found the two youngest samples had an average age of 35 million years, which confirms other estimates for when the Chesapeake Bay crater formed. And this has implications for other research, too. The study’s lead author Marc Biren said in a statement, quote, "Our results demonstrate the uranium-thorium-helium dating method's viability for use in similar cases, where shocked materials were ejected away from the crater and then allowed to cool quickly, especially in cases where the sample size is small," unquote. Rock on!
Why Do Birds Sing? — https://curiosity.im/31WBWlQ (Republish) (Cody)
Have you ever wondered why birds sing? As reported by The Conversation, it turns out there are two main purposes, and they are connected. First, male birds sing to mark their territory. A singing bird is basically saying he owns the place, and he’s gonna defend it, especially from other birds. That bird is so serious about this, he might even patrol his space and sing often, either from the middle or from the edges of what he thinks of as his turf.
The second purpose of singing is for romance. A lot of the time, female birds choose their mates based on a blend of visual and vocal cues. Even good-looking male birds with beautiful breeding-season plumage can have a hard time finding mates if their songs don't measure up.
Each bird species typically has its own unique song. That helps an individual bird be able to hear a song and recognize whether the singer is from its own species.
Since singing helps birds get in the mood, you’ll hear them singing the most often during nesting season. After the nesting period is over, birds sing a lot less and their territories break down.
Oh, and migration also gets birds chatting away. For example, when birds fly south in the fall, they make little "chip" notes or "contact calls" that help them stay in touch with other birds.
One more thing about bird songs: for a lot of bird species, only the males sing, though there are some where both males and females do. And some birds don't sing at all. For example, vultures and storks can barely produce any sound — let alone something musical enough that we would call it a song.
That pretty much covers birds singing, but how about people? You’ve maybe heard of bird watching, or birding, but there are people who can identify birds by their songs, too. In fact, some enthusiasts might say that good ears are just as as important as good eyes when it comes to really appreciating the birds you come across. Next time you’re strolling around and you’re caught up on your podcast episodes, try taking off your headphones and listening to the sounds of your neighborhood birds — especially when they’re active in the morning or evening. You might be surprised by what you hear.
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Why Do Bruises Change Color? — https://curiosity.im/2ZuFgDn (Ashley)
Bruises come in lots of different colors. And whether you’ve taken a tumble on your bike or banged your shin on a coffee table, chances are you might’ve wondered why your bruises went from pink and red to blue and dark purple. So here’s the science behind what’s going on under your skin to make your latest boo-boo turn all the colors of the rainbow. A bruise happens in the first place when some sort of trauma damages your blood vessels but doesn’t break your skin. Tiny blood vessels called capillaries are sandwiched between your skin and other tissues in your body, so when they burst, their contents get trapped there. Your body's job is to reabsorb the leaked blood, leading the bruise to eventually heal. And the healing process is a colorful one. Bruised capillaries release fresh blood that's colored red by hemoglobin. That’s a protein that transports oxygen throughout your body. The oxygen-rich blood causes the injury to appear reddish at first. But after one or two days without circulation, the hemoglobin begins to break down, coloring the bruise blue, purple, or even black. As the trapped hemoglobin breaks down, your body essentially repurposes it for spare parts. For example, the iron in hemoglobin can be used to make new red blood cells. With that iron gone, the decomposed hemoglobin turns into biliverdin, which is a green pigment responsible for the olive hue of a week-old bruise. Finally, your bruise will turn yellow or light brown to mark the end of the healing process. That color comes from bilirubin, which is a byproduct of hemoglobin breakdown that's also responsible for jaundice. Once your liver filters out the bilirubin, your bruise should fade away. Oh, and as for the shape of your bruise: If you've ever taken a nasty direct hit, like being shot by a paintball gun or nailed by a baseball batter's line drive, you’ve maybe seen a bruise heal in a donut shape, with a ring of darkened bruising around a lighter center area. That's called central clearing, and it happens when the trauma is severe enough to force blood away from the point of impact. And now that you know all about bruises: we hope you don’t get one any time soon!
CODY: And now, let’s recap what we learned today. Today we learned that scientists used uranium-thorium-helium dating to confirm that the Chesapeke Bay impact crater formed about 35 million years ago.
ASHLEY: And that birds sing to mark their territory, and to attract mates
CODY: And that your bruises change colors because of the way your body breaks down your broken capillaries
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CODY: Join us again tomorrow to learn something new in just a few minutes. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Stay curious!